


The Chemical Formula of Love

by oldamongdreams



Category: Sherlock (TV)
Genre: Asexual Sherlock, Cuddling & Snuggling, First Kiss, First Time, Hand Jobs, Is this Fluff? Did I actually write Fluff?, M/M, tattooed!Sherlock
Language: English
Status: Completed
Published: 2013-01-11
Updated: 2013-01-11
Packaged: 2017-11-25 03:39:05
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,861
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/634717
Author URL: https://archiveofourown.org/users/oldamongdreams/pseuds/oldamongdreams
Summary: <blockquote class="userstuff">
              <p>Sherlock stood, walking slowly around the table as he spoke. “You want to ask me about my tattoo, the one you caught a glimpse of at the crime scene. You’re interested because it doesn't fit with the picture you have of me, and you’re beginning to wonder what else you may have missed though not observing the facts around you.” Sherlock paused when he was directly behind John’s chair, so close that John could feel the warmth emanating from him.<br/>“Unless there’s some other reason you've been staring at me more than usual for the last week?” He asked archly, one hand brushing against John’s shoulder before he moved away.</p>
            </blockquote>





	The Chemical Formula of Love

The first time John saw Sherlock’s tattoo was, predictably enough, at a crime scene. It was unseasonably warm, to the point where Sherlock had gone so far as to discard his coat and roll up the long sleeves of his shirt.

Sherlock was leaning over a body, muttering to himself about the ring on the dead man’s finger and something being out of place, and as he stretched forward to grab the man’s left wrist, his shirt lifted slightly.

John, (who had by no means been staring at Sherlock’s arse, but rather glancing at nothing particular in that direction) blinked once in surprise as the motion revealed several sharp black lines that stood out in contrast to Sherlock’s pale skin. He hadn’t even had a chance to open his mouth—though what he would say, John had no idea—before Sherlock had jumped up, tucking his shirt back in and collecting his coat from the ground, and sped off in the direction of a cab, shouting deductions at Lestrade all the while.

John gave a half-wave by way of apology, and followed after the man.

 

It was a week before John dared to broach the subject. The case had ended— _“It was the gardener. Obvious,”_ Sherlock had announced scornfully two days previously—and John could sense that Sherlock was already sinking into a fit of boredom that had the potential to destroy the flat. He told himself that that’s the only reason he asked, that it had nothing to do with the way the contrast of dark lines on pale skin had played out before his mind whenever he closed his eyes.

“What do you think about tattoos?”

Sherlock surveyed John’s face for a moment and shrugged. “I don’t think much about them at all,” he said in a dry voice. “Are you sure that’s what you really want to ask me?”

“Tell me then, what is it I’d _really_ like to ask you?”

Sherlock stood, walking slowly around the table as he spoke. “You want to ask me about my tattoo, the one you caught a glimpse of at the crime scene. You’re interested because it doesn’t fit with the picture you’ve created of me, and you’re beginning to wonder what else you may have missed though not observing the facts around you.” Sherlock paused when he was directly behind John’s chair, so close that John could feel the warmth emanating from him.

“Unless there’s some _other_ reason you’ve been staring at me more than usual for the last week?” He asked archly, one hand brushing against John’s shoulder before he moved away.

By the time John had recovered enough to turn around, Sherlock had disappeared into his bedroom and the door had closed behind him.

 

The thing was, Sherlock was right. Not about the ‘other reason’, whatever he had meant by that, but about John staring at him more than usual. He couldn’t help it; it was like that first drug bust all over again, insisting that Sherlock would never do drugs before having the tables turned on him.

He wasn’t trying to stare, he just couldn’t help it. What else had he missed? The more he looked, the more he noticed.

He noticed the way Sherlock’s eyes changed colour when he was angry or deep in thought about something.

He noticed the way Sherlock’s hair lay almost flat when it was wet, except for the bits around his ears.

He noticed the way Sherlock would become increasingly more restless the longer he went without sleep, clenching and unclenching his fists and slapping on more nicotine patches than could in any way be healthy.

He noticed Sherlock’s lips, far more than he would ever admit, and refused to analyse that too closely.

Sherlock noticed John noticing him. _Obviously._ He didn’t comment on it though, at least not verbally. Physically though…well, John had to admit that he wasn’t entirely sure if Sherlock had changed as much as he thought, or if he just hadn’t noticed before. But slowly, he could see that things were changing, that Sherlock was acting differently in subtle ways.

Milk began to appear in the fridge on an almost regular schedule. Experiments were (mostly) labelled and confined to the bottom two shelves of the fridge. Despite Sherlock’s obvious boredom without a case, he refrained from stealing John’s gun.

John let it go without comment, fearing that if he said anything about the changes he had noticed, Sherlock would stop just to be contrary. After all, while the behaviour was strange, it was a good strange for once. And that was a change John was more than willing to accept.

 

Another week passed this way, in this redefined ‘normal’ at Baker Street. Lestrade’s odd looks in John and Sherlock’s direction when they were invited out on another case was enough to tell John that he wasn’t imagining that something was different about Sherlock—even if he wasn’t sure quite what it was.

“Have you eaten today at all?” John called across the room after they had returned from the crime scene where Sherlock, uncharacteristically, had actually waited for John before speeding off in a cab.

Sherlock didn’t answer, which John took to mean he had not. “I’m going to order takeway,” he continued. “Is there any point in asking what you’d like, or should I just order doubles of whatever I’m having so that when you refuse to eat it I’ll have lunch for tomorrow?”

“John,” Sherlock called, and John turned back to look at the man. Sherlock was wearing an expression John was quite certain he had never seen before, a strange mixture of hesitancy and nervousness that looked out of place on his usually confident face.

“Yes?” John asked curiously.

Sherlock stared at him for a moment, and then closed the distance between them in three brief strides and pressed his lips to John’s.

The kiss was clumsy and unpractised, with a vulnerability that surprised John. He stood there in shock for a moment before pulling slightly away from Sherlock.

What he intended to say was something along the lines of ‘no, I’m not interested, I’m sorry but you’ve read this all wrong’, but what came out was “But I thought you were married to your work?”

“Which you have become an irreplaceable part of,” Sherlock replied with dry amusement.

“But you—I thought you weren’t interested in any of this.”

“John,” Sherlock said softly. “I bought you milk.” It was a simple sentence, but one laced with more meaning than John could possibly grasp. _To hell with it,_ he thought and pressed his lips back to Sherlock’s, because what else was he supposed to do with a mad flatmate who saw doing the shopping as some sort of bizarre courtship ritual?

“Interesting,” Sherlock whispered against John’s lips, before pressing his face into John’s shoulder. He muttered something that sounded suspiciously like “latent bisexual tendency,” and John snorted.

“I swear, if you overanalyse this…” He mouthed at the shell of Sherlock’s ear, causing the man to shudder violently. “Just. Don’t.”

Sherlock moaned in what might have been agreement and pressed his lips back to John’s. John licked his way into Sherlock’s mouth, giving himself over to the sensations that accompanied having this permission—a permission he hadn’t even known he wanted—to touch and kiss and map the body that had previously been untouchable.

 “You know, I could get used to this,” John mumbled against Sherlock’s skin. One of his hands drifted lower to cup the front of Sherlock’s trousers.

Sherlock pulled away with an abruptness that startled John, not stopping until he was an arm’s length away.

“Are you okay?” John asked with a frown, noticing a blush that had begun to spread across Sherlock’s face and neck, and resolved to turn him that colour again, under a more amiable circumstance than whatever was currently happening.

“I don’t—” Sherlock began haltingly, his breath still uneven. “I, um, you don’t have to do, you know, that.” He gestured at his pants, his blush spreading. “I don’t mind getting you off, and I like the kissing and touching, but I don’t want you to try to get me off.”

This time it was John who took a step back, raising both his hands slowly so as to not startle Sherlock. “Look, I didn’t mean to push you. We can just pretend that this never happened, if that’s what you would prefer?”

Sherlock growled softly and shook his head. “Idiot. That’s not what I said. I kissed you first, remember?” He waited for John to nod in conformation. “Despite whatever you might be thinking, I am not some blushing virgin you have to take care of. I have had sex before, it’s just not something I find particularly stimulating or enjoy being on the receiving end of. I thought I would inform you before we take this any further, but I by no means wish to stop entirely.”

John stared blankly at Sherlock. “If you’re sure, then,” he said doubtfully, and Sherlock sighed impatiently.

“Have you ever seen me willingly do something that I did not want to do?” Sherlock demanded, stepping closer to John, crowding into him all at once and dipping his head to brush his lips against the shorter man’s neck.

“This is something I want,” he murmured, punctuating the sentence with a sharp bite to the junction of John’s neck and shoulder. “And something I suspect you want as well, though you were taking far too long to actually act upon it.”

“Fuck,” John swore softly, and Sherlock raised his head to grin at him.

“Maybe if you’re very, _very_ good,” he purred, before grabbing John’s hand and tugging him toward the bedroom.

They collapsed on Sherlock’s bed in a giggling heap, and Sherlock immediately crowded back into John, nipping at his chest as he stripped him of his shirt.

“Bloody vampire,” John growled as he fumbled with Sherlock’s own buttons, doing his best to keep from rutting against Sherlock’s thigh. He could see the marks of the tattoo on Sherlock’s side more clearly now—some sort of chemical formula drawn to look as though the skin around it had been ripped to expose it. He wanted a closer look, but Sherlock’s perfect lips were too distracting for him to even pretend he would be able to focus on the tattoo.

Sherlock muttered something John couldn’t quite catch, but suspected was a derisive comment about either vampires or John’s lack of deductive reasoning before pulling back to strip his shirt all the way off. His hands hesitated for a moment at the buckle of his trousers, and Sherlock gave John a speculative look.

“I’m keeping my pants on,” he said, even as he slid his trousers down his thighs and kicked them to the floor. “It’s not that I don’t trust you, but I sometimes find that it’s better to distance oneself from temptation.”

John nodded, his hands resting at his own belt. “Do you want me to...I mean…”

“Oh, for God’s sake,” Sherlock sighed, and reached over to undo John’s belt himself, purposefully brushing his fingers against the bulge in his trousers. “I am quite looking forward to documenting each and every sound you make,” he said in a dark voice that in no way ought to have been as seductive as it was, then latched his mouth around John’s left nipple.

John moaned, and gave in. As usual, he would give Sherlock whatever it was he wanted, and it appeared that he wanted to watch John come to pieces beneath him.

John obliged, rutting against Sherlock until skilled fingers took him in hand, twisting around John’s length in a way that made John think he would be very lucky if he didn’t combust from the sensations of Sherlock touching him, mouthing at his chest, and moaning in return as John stroked along his back and kissed down his neck.

He was barely able to whimper a warning to Sherlock before he felt his orgasm crash over him, shrinking his world to the sensations of pleasure sparking inside him.

When John was able to focus again, he saw Sherlock peering down at him, his lips pursed. “Interesting, but I think I need more data.” He said as he rolled off John, wiping his hand clean on the sheets.

“I wouldn’t be opposed to a repeat experiment if you aren’t,” John said, catching hold of Sherlock’s arm before he could slide out of the bed. “Where do you think you’re going?”

“Out,” Sherlock said, as though it were obvious. “I didn’t think you’d want me here, now that you’ve gotten off.”

“Why wouldn’t I want you here?” John said with some confusion, sighing as he caught sight of the vulnerable look on Sherlock’s face. “Come back to bed, Sherlock. Besides, it’s my turn now.”

The look on Sherlock’s face turned wary, and he tried to tug his arm away from John. “I thought I expressed to you that I have no interest in—”

“Not like that, you git,” John replied, rolling his eyes and sitting up. “I want to touch you. I want to learn you and watch your face while I do it. If I do anything that makes you uncomfortable, tell me and I’ll stop.”

Sherlock hesitated, but nodded and perched on the corner of the bed. John wiped himself off with the sheet Sherlock had used before crumpling it up and throwing it to the floor. He kissed Sherlock softly, and then pulled away. “Is this okay?” He asked.

“I think I have already expressed that I quite like kissing,” Sherlock said, chasing after John’s mouth with his own. John made a quiet noise of approval before moving his lips down to Sherlock’s neck, intent on exploring every inch of skin that Sherlock would allow him to touch.

Sherlock tensed when John’s lips reached his navel, and John carefully moved back up and to the side, tracing first Sherlock’s ribs, then the lines of his tattoo with his tongue. “Next time I’m getting massage oil,” he whispered against Sherlock’s skin. “I am going to rub all the tension out of you until you’re just a boneless heap on the mattress.”

“You’re doing a pretty good job of that with just your lips,” Sherlock said in a low voice, tugging at John until he met Sherlock’s lips with his own once more.

“So, now will you tell me about it?” John asked softly, breaking the comfortable silence and running his fingers over the tattoo inked on Sherlock’s side.

“Why don’t you tell me what you’ve observed?”

“Well…these are obviously chemical formulas of some sort. That’s a DNA strand in the background.”

“Could have been more detailed, but you got the basic points across.” Sherlock let his own fingers drift down to cover John’s before he spoke again. “I got it in university. I don’t quite remember why, but then, that’s a period of my life where I have quite a few gaps in my memory.”

John tensed slightly at Sherlock’s oblique reference to the drug addiction he had fostered in the years before they had met, but nodded for Sherlock to continue.

“It’s exposing my body for what it really is—or was, back then.” He tugged at John’s fingers, running them along the edge of the tattoo before settling on one of the formulas. “Cocaine,” he said bluntly. “Adrenaline, and haemoglobin. Drugs, Adrenaline, Blood, and DNA. If I were a machine, then that’s all I needed to survive. I’ve debated getting it removed, but I haven’t seen a reason to do so since it’s positioned in a way that’s not normally visible.”

His eyes had closed at some point during his speech, reliving memories that John could never be a part of.

John stroked his fingers against the tattoo again, softly. “I like it,” he said. “It’s very you, getting chemical formulas tattooed on you. If it had been some sort of tribal tattoo I would have lost all respect for you.”

Sherlock looked at John in confusion. “Why on earth would I get tribal markings tattooed on my skin?”

“Never mind,” John said with a smile, pulling Sherlock flush against him. “On another note, purely hypothetical of course, what are your thoughts on cuddling?”

“I would not be adverse to the idea, if you insist upon it,” Sherlock said, hiding his smile against John’s shoulder as he let himself relax into John’s warm embrace.

 

Several months later, the post-case high found them both in Sherlock’s bed, as was becoming the norm whenever a case wasn’t keeping Sherlock from indulging in anything he considered unnecessary. John had his head pillowed on Sherlock’s chest and his fingers spread across the new lines adorning Sherlock’s tattoo.

“I give up. Tell me genius, what do they mean?”

A faint blush crept onto Sherlock’s cheek as he answered. “It’s the chemical formula for Oxytocin.”

Oxytocin. Often referred to as the ‘love hormone’ or the ‘trust hormone’. John felt a smile slowly spread across his face, and he leaned down to brush a kiss across the stark black lines of Sherlock’s declaration. 

**Author's Note:**

> Images of what Sherlock's tattoo looks like can be found here, if you are so inclined: http://oldamongdreams.tumblr.com/post/40267701521  
> Beta'd, as always, by the lovely lemonadesummers11.


End file.
